According to StatCounter, the weekly share of Windows 7 usage went from 1.75% pre-launch to 2.82% at the end of October. Those stats were specific to the US, but global market share increased at the same rate. Windows usage overall (meaning all versions of Windows), however, was down slightly month-over-month, according to Net Applications.
Here are the US and global statistics from StatCounter:
Source: StatCounter Global Stats - Operating System Market Share
Source: StatCounter Global Stats - Operating System Market Share
Mac OS X Usage Also Up
Windows 7 wasn't the only OS that saw increases in adoption in October. Both Net Applications and StatCounter also showed an increase in Mac OS X usage. According to StatCounter, Mac OS X usage grew from 11.29% in the US to 11.87%. Net Applications global statistics showed a growth of 5.12% to 5.26%.
The big takeaway is that whether users are using Windows 7 or Mac OS X, adoption to newer operating systems is starting to ramp up.